In the related art, scanning probe microscopes (SPMs) have been used for measuring a characteristic of a sample while scanning the sample in a state where a fine probe (a short needle) is in contact with the front surface of the sample. Examples of these scanning probe microscopes include scanning spread resistance microscopes (SSRMs) and the like, which are used to measure the carrier concentration distribution of a transistor.
In the scanning probe microscopes according to the related art, if a contact type probe scans the front surface of a sample, the sample and the tip of the probe wear down, thereby generating abrasion powder. The abrasion powder may stick between the probe and the sample to possibly cause a bad electric connection between the probe and the sample and deteriorate the accuracy of measurement by the probe.
Also, the deterioration of the measurement accuracy may be aggravated by the scanning trajectory of the probe. The scanning trajectory of the probe of the scanning probe microscope according to the related art includes a measurement trajectory along which the probe measures the characteristic of a sample while scanning the front surface of the sample, and a non-measurement trajectory along which the probe does not measure the characteristic of the sample although the front surface of the sample is still scanned. Examples of the non-measurement trajectory include a scanning trajectory that is formed when the probe moves between a plurality of measurement trajectories, and a scanning trajectory that is formed when the probe moves from a point on the front surface of the sample with which the probe comes into contact for the first time, up to a point on the front surface of the sample from which the probe starts to measure the sample. Although not contributing to measurement on the sample, the non-measurement trajectory generates abrasion powder, and thus aggravates deterioration of the measurement accuracy due to abrasion powder.